Strainer basket and lid O-ring
The pump strainer basket (Pentair part 353971 for WhisperFlo, 356879 for IntelliPro wet end) captures debris before it enters the impeller. Inspect monthly and clean when 1/3 or more full. The lid O-ring (Pentair part 273518) seals the strainer basket lid -- a worn O-ring causes air intrusion into the suction line, which causes priming problems and reduces pump efficiency. Replace the lid O-ring annually as preventive maintenance ($5-$10 at pool supply retailers). Lubricate the O-ring with a thin coat of silicone-based grease (never petroleum-based -- degrades rubber) before installation.
Impeller replacement
The pump impeller is inside the wet end (the plastic housing connected to the motor). If the pump runs but flow rate has decreased significantly without a change in filter condition or valve positions, the impeller may be worn or partially clogged. Access: remove the pump from the plumbing, unbolt the wet end from the motor, and remove the impeller (counterclockwise -- impellers are reverse-threaded to prevent loosening during pump rotation). Order the replacement impeller by Pentair pump model number (listed on the motor housing label). Cost: $25-$80 depending on model. Inspect the diffuser plate at the same time -- replace if the vanes are worn or chipped.
IntelliPro drive board
The IntelliPro VSF's variable speed control is managed by a motor drive board inside the motor housing. If the motor runs erratically (speed fluctuations, error codes on the display, or failure to start) and all external connections check out correctly, the drive board may be faulty. Pentair drive board replacement is available through Pentair dealers and pool supply distributors (cost: $300-$500 for the drive board). This repair is within the skill set of experienced pool equipment technicians but requires safe handling of high-voltage electronics with pump power fully disconnected. Within the IntelliPro's 2-year warranty: contact Pentair at 1-800-831-7133 for warranty service.
Pentair 2-year warranty
Pentair covers IntelliPro VSF under a 2-year limited warranty and WhisperFlo under a 1-year limited warranty for manufacturing defects. Contact Pentair at 1-800-831-7133 or pentair.com with the pump serial number, installation date, and installer information. Pool pump warranty typically requires professional installation (licensed pool contractor) for coverage -- retain installation documentation. Parts and warranty service for pool pumps are provided through the Pentair authorized dealer network rather than direct consumer service.